Arbor for securing a workpiece

ABSTRACT

A male arbor having axially spaced annular sections of different diameters and adapted to retain a female workpiece having a multi-diameter internal bore. Each of the annular sections includes a hub member, with the hub members coupled to each other. Annular members are carried by each of the hub members, with one of the annular members of each pair slidably mounted. Opposing tapered wedging surfaces define grooves for receiving balls which normally project radially from the grooves to grip the workpiece and which are retracted into the grooves upon axial separation of the annular members so that the workpiece can be removed from the arbor. Each annular section includes one of the annular members provided with a plurality of circumferentially spaced and longitudinally disposed bores extending therethrough and including a decreased diameter portion in axial alignment with a plurality of circumferentially spaced and longitudinally disposed threaded bores in the adjacent annular member. A plurality of threaded fastening members slidably extend through the bores in one annular member to be received by the bores of the adjacent annular member. The shank portion of each fastening member is of such a length as to permit axial movement of each movable annular member relative to the adjacent annular member. A plurality of springs carried by each of the shank portions of each fastening member exert a biasing force against its associated movable annular member to bias the same toward its adjacent annular member. The biasing force of the springs and thus the force projecting the balls radially from their associated grooves may be selectively varied.

United States Patent [1 1 Hernandez [451 Feb. 19, 1974 ARBOR FORSECURING A WORKPIECE [75] Inventor: Manuel R. Hernandez, Westland,

Mich.

[52] US. Cl 2159/48.], 269/52, 269/229, 279/2 [51] Int. Cl B23q 3/14,B23b 31/40 [58] Field of Search 269/47, 48.1, 52, 196, 199, 269/200,229; 279/2; 82/44 [56] References Cited UNITED STATES PATENTS 963,6037/1910 Lunceford 269/48.l 1,235,957 8/1917 Bidwell 279/2 1,407,1452/1922 Gasteiner 279/2 2,499,781 3/1950 Rothenberger 279/2 2,698,5511/1955 Olsen 279/2 X 2,775,137 12/1956 Chung 192/150 X 2,821,946 2/1958Goekler 269/48.1

2,870,686 1/1959 Smith 279/2 X 2,967,462 1/1961 Yogus 279/2 X 2,989,3166/1961 Perry et al. 279/50 3,100,117 8/1963 Schneider et a1. 279/66Primary Examiner-Othell M. Simpson Assistant Examiner-Joseph T. ZatargaAttorney, Agent, or Firm-Haukc, Gifford, Patalidis & DuMont 57 1ABSTRACT A male arbor having axially spaced annular sections ofdifferent diameters and adapted to retain a female workpiece having amulti-diameter internal bore. Each of the annular sections includes ahub member, with the hub members coupled to each other. Annular membersare carried by each of the hub members, with one of the annular membersof each pair slidably mounted. Opposing tapered wedging surfaces definegrooves for receiving balls which normally project radially from thegrooves to grip the workpiece and which are retracted into the groovesupon axial separation of the annular members so that the workpiece canbe removed from the arbor. Each annular section includes one of theannular members provided with a plurality of circumferentially spacedand longitudinally disposed bores extending therethrough and including adecreased diameter portion in axial alignment with a plurality ofcircumferentially spaced and longitudinally disposed threaded bores inthe adjacent annular member. A plurality of threaded fastening membersslidably extend through the bores in one annular member to be receivedby the bores of the adjacent annular member. The shank portion of eachfastening member is of such a length as to permit axial movement of eachmovable annular member relative to the adjacent annular member. Aplurality of springs carried by each of the shank portions of eachfastening member exert a biasing force against its associated movableannular member to bias the same toward its adjacent annular member. Thebiasing force of the springs and thus the force projecting the ballsradially from their associated grooves may be selectively varied.

5 Claims, 3 Drawing Figures PATENTEDfEBI 9 I974 FIG-3 INVENTOR MANUEL RHERNANDEZ Attorneys ARBOR FOR SECURING A WORKPIECE CROSS REFERENCE TORELATED PATENT BACKGROUND OF THE INVENTION I. Field of the Invention Thepresent invention relates to arbors for mounting a workpiece and, inparticular, to an arbor having means for variably controlling theretaining force exerted by the arbor on the workpiece.

II. Description of the Prior Art Heretofore, numerous apparatus anddevices have been employed to engage and hold a workpiece so as tofacilitate a working operation thereon. Preferably such workpieceholders should be able to grasp the workpiece in a firm manner toaccurately position the workpiece with respect to the tool which is toeffect a working operation on the workpiece. It is particularlydesirable that the workpiece holders be of such a nature that they canbe quickly engaged and disengaged with the workpiece, yet that they beof sufficient strength to prevent the accidental separation of theworkpiece from the holder, as such an accidental separation during aworking operation could result in damage to the workpiece or to theholder and could cause injury to the operator.

It would thus be desirable to provide a workpiece holder which has acoupling structure which can be quickly engaged with and disengaged froma workpiece and yet which is constructed in a manner which minimizes thedanger of an accidental separation during the working operation.

SUMMARY OF THE INVENTION The present invention, which will be describedin greater detail hereinafter, comprises an arbor having a pair ofaxially positioned, relatively movable annular members biased toward oneanother and having means for mounting a plurality of circumferentiallyspaced gripping balls that are radially displaceable to engage and gripa workpiece when the annular members are moved toward one another. Meansare provided for adjustably selecting the force biasing the annularmembers toward each other to thereby vary the retaining force exerted bythe gripping balls on the workpiece.

It is therefore an object of the present invention to provide a new andimproved arbor having means which permits the selective control of thegripping forces exerted by the arbor upon a workpiece.

It is also an object of the present invention to provide an arbor whichis simple in its construction, easy to operate and yet of such a designas to prevent the accidental separation of a workpiece carried thereby.

Other objects, advantages, and applications of the present inventionwill become apparent to those skilled in the art of arbors when theaccompanying description is read in conjunction with the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING The description makes reference to theaccompanying drawing wherein like reference numerals refer to like partsthroughout the several views, and in which:

FIG. 1 is a longitudinal cross-sectional view through an arborconstructed in accordance with the principles of the present invention;

FIG. 2 is a transverse cross-sectional view of the arbor taken alongline 2-2 of FIG. 1; and

FIG. 3 is a transverse cross-sectional view of the arbor taken alongline 3-3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing,there is illustrated a male arbor 10 constructed in accordance with theprinciples of the present invention, however, it is to be understoodthat the inventive concept disclosed herein has general application andmay be employed in a variety of devices where ball grip means areemployed, as, for example, female arbors, tool holders, gauges, chucksand other well known workpiece holder devices.

The male arbor 10 is adapted to support a female workpiece 12 having alongitudinal bore 13 of a diameter D and a radially enlarged end bore 15of a diameter D The arbor 10 comprises a pair of coupled and axiallyspaced gripping ball retaining assemblies 14 and 16. The assembly 14comprises a cylindrical hub member 18 having a radially enlarged annularflange member 20 and a longitudinal bore 22 within which is disposed ashaft 24 that supports the assemblies 14 and 16. Although it has beenpreferred to illustrate the assembly as including a shaft 24, it is tobe understood that in some embodiments of the invention such a shaftwill not be necessary and, therefore, will not be used. The cylindricalhub member 18 is fixedly secured to the shaft 24 by a set screw 26extending through a radially disposed bore 28 in the hub member 18 andinto an abutting engagement with the outer periphery of shaft 24.

The outer peripheral surface 29 of the cylindrical hub member 18slidably supports an annular member 30. The opposing faces 31 and 33,respectively, of the annular member 30 and the flange member 20 have,proximate their peripheral surfaces, cooperating, wedging surfaces whichdefine an annular V-shaped groove 32 within which are disposed aplurality of circumferentially spaced gripping balls 34, each ball 34being held in position by an annular retainer ring 36. The ring 36 has aplurality of peripherally spaced apertures 37 having a diameter slightlyless than the diameter of the gripping balls 34, such that each ball 34protrudes radially outwardly through its respective aperture 37 apredetermined limited distance from groove 32. The retainer ring 36 hasan outer diameter substantially the same as the outer diameters of theannular member 30 and the flange member 20, such that the outerperipheral surface of the ring member 36 is substantially flush with theouter peripheral surfaces of the members 20 and 30 when the retainerring 36 is seated in opposing peripheral recesses 38 formed in theannular member 30 and flange member 20.

It can thus be seen that during assembly of the arbor 10, the ringmember 36 is first inserted in the recess 38 in the flange member 20 andthe gripping balls 34 are then placed within the apertures 37 of theretaining ring 36. The annular member 30 is then positioned on the outersurface 29 of hub member 18, thereby locating the balls 34 and retainerring 36 in a proper position with respect to groove 32.

As can best be seen in FIGS. 1 and 2, the annular member 30 has aplurality of arcuately spaced and 1ongitudinally disposed bores 39opening at one end to the outer face 43 of the member 30 andcommunicating with the inner face 31 through smaller and axially alignedbores 40 which, in turn, are adapted to be axially aligned with aplurality of circumferentially spaced and longitudinally disposedthreaded bores 42 opening to the face 33 of the flange member 20.

"resisting memento; steaming; Steamers? portion 46 and an enlarged headportion 48 are, respectively, slidably disposed in bores 40 and 39,while a threaded end portion 50 of each fastening member 44 isthreadingly received in the aligned bores 42 in the flange member 20. Ashoulder 52 at the end of the shank portion 46 of e a c h o f th efastening members 44 tightens against a shoulder 53 in the threadedbores42 to securely lock the fastening members 44 in place. A spring 54within each of the bores 39 surrounds the shank portion 46 of fasteningmember 44 with one end of the spring 54 bearing against washers 55encompassing the fastening members 44 adjacent the bottom of the bore39, while the other end of the spring 54 bears against the underside ofthe head portion 48 of its respective fastening member 44 to exert aforce on the annular member 30 to bias the same toward the flange.

member 20, that is, to decrease the size of the V- shaped groove 32. Thewashers SSprovide a convenient means for varying the tension of thesprings 54 with more or less washers 55 in place increasing ordecreasing respectively the force exerted by the springs The movement ofthe arbor into the female workpiece 12 produces a downward force on theballs 34, causing axial separation of the flange member 20 and theannular member 30 to deepen the grooves 32 to accommodate the balls 34.As the annular member 30 separates from the flange member 20, each ofthe springs 54 is further compressed and exerts a force of apredetermined amount on the member 30 to resist axial movement and tobias the balls 34 when the arbor 10 is in position, radially outwardlyinto a retaining engagement with the surface of the bore of the femaleworkpiece l2 and thus securing the same to the arbor l0.

1 The assembly l6 skirtin as sembly 14 in that it comprises acylindrical hub member 60 having a radially extending circular flangemember 62, an annular surface 64 slidably supporting an annular member66 and a longitudinal bore 68 through which shaft 24 extends. Theopposing adjacent faces 70 and 72, respectively, of the annular member66 and flange member 62 have cooperating wedging surfaces defining aV-shaped groove 74 within which is disposed a plurality of grippingballs 76. The gripping balls 76 are retained within the groove 74 by aretainer ring 78 disposed in peripheral recesses 80 in the members 66and 62, such that the outer peripheral surfaces of the members 62 and 66are flush with the outer peripheral surface of the retainer ring 78 inthe same fashion as hereinbefore described with respect to the retainerring 36. The retainer ring 78 also has a plurality of peripherallyspaced apertures 79 having a diameter less than the diameter of thegripping balls 76, such that each ball 76 protrudes radially outwardlythrough its respective ap,

erture 79 a limited distance.

The movable annular member 66 is also provided with a plurality ofcircumferentially spaced bores 82, each having a decreased diameter bore84 axially aligned therewith and with threaded bores 86 in the flangemember 62. Fastening members 88, which are of the same construction asthe fastening members 44, slidably extend through bores 82 and 84 andthreadedly engage the bores 86 in the flange member 62 to permit limitedaxial movement of the annular member 66 with respect to the flangemember 62 in the same manner as hereinbefore described with respect tothe ball retaining assembly 14.

Springs 90 and washer 91 are disposed in the bores 82 surrounding theshank portion of each of the fastening members 88. Each spring 90 hasone end bearing against the washers 91 while the other spring end bearsagainst the underside of a head portion 94 of each fastening member 88to bias, with a predetermined amount of force, the annular member 66toward the flange member 62 tending to thus radially project the balls76 into engagement with the surface of the bore 13 of the femaleworkpiece 12.

The hub member 18 has a threaded neck 96 which engages a threaded bore98 in the hub member 60 to secure the two assemblies 14 and 16 togetherand to form the unitary arbor 10. Since the outer diameter of the ballretaining assembly 14 is slightly less than the inner diameter D ofworkpiece l2 and the outer diameter of the ball retaining assembly 16 isslightly less than the inner diameter D of the workpiece 12, the arbor10 will firmly grip at separate locations a female workpiece havingdifferent internal diameters.

The male arbor 10 is manipulated by grasping the female workpiece 12 andinserting the male arbor 10 into the interior bores 13 and 15 of theworkpiece 12, with the smaller diameter portion assembly 16 of the arbor10 first inserted into the bore 13, followed by the larger diameterportion assembly 14 being inserted into the bore 15, such that grippingballs 34 and 76 wedge the arbor annular members 30 and 66 and flangemembers 20 and 62 longitudinally slightly apart. This action will exertan outwardly directed force against each of the gripping balls 34 and 76to firmly secure the female workpiece 12 to the arbor 10. The release ofthe aibor 10 from the workpiece 12 is accomplished simply by pulling theworkpiece 12 off the arbor 10, whereupon the balls 34 and 76 areprojected radially outward by the return movement of the annular membersligand 66 to theirno-load condition.

The amount of gripping forceexerted by the gripping balls 34 and 76 onthe inner peripheral surfaces of the workpiece 12 is a function of thebiasing force of the springs 54 and 90, that is, the force tending tomove the annular members 30 and 66 toward their adjacent flange members20 and 62. If the spring force is increased, the gripping force islikewise increased, and if the spring force is decreased, then thegripping force available to hold the workpiece I2 is likewise decreased.The spring force can, of course, be changed by providing more or lesswashers 55 and 91.

The present construction of the arbor 10 provides a simple but veryaccurate and effective means of controlling the spring force and thusthe gripping force exerted on the workpiece 12 by the gripping balls 34and 76. By simply adding or subtracting washers 55 and 91, the amount ofprecompression at each of the plurality of springs54 and 90iscontrolled, and thus the biasing force urging the annular mem-bersjfland 66 toward message members and 62 may be selectively adjusted. Bycontrolling the force exerted by springs 54 and 90, the depth of theV-shaped grooves 32 and 74 and thus the gripping force exerted by theballs 34 and 76 on the workpiece 12 is then easily controlled.

it can thus be seen that the present invention .provides a simplebiasing means for coupling an annular member to a flange member of anarbor while at the same time providing for the selective control of theamount of biasing force available.

Although only one embodiment of the present invention has beendisclosed, it is to be understood by those skilled in the art of arbors,that other forms may be had all coming within the spirit of the presentinvention and the scope of the appended claims.

What is claimed is as follows:

1. A means for receiving and retaining a workpiece or the likecomprising:

a pair of axially spaced and relatively movable members having adjacenttapered wedging surfaces defining a ball receiving groove;

gripping balls in said groove, said gripping balls normally projectingradially from said groove in response to the relative axial approach ofsaid members, said gripping balls being retracted into said grooves inresponse to the relative axial separation of said members;

means limiting the radial projection of said balls from said groove whensaid members approach one another;

means coupling said members to one another;

said coupling means comprising a plurality of circumferentially spacedand longitudinally disposed bores in one of said members, aplurality offastening screws extending through said bores and threadedly engaging aplurality of axially aligned and circumferentially spaced threaded boresin the other of said members, a plurality of springs disposed in saidfirst mentioned bores and wound around said fastening screws, saidsprings engaging a portion of their associated fastening screws andbores to bias said one member toward said other member.

2. The means defined in claim 1 wherein said other of said members has ahub portion and said one member has a bore axial aligned with andslidably engaging said hub portion such that said one member is axiallyslidably movable on said hub portion to and away from said other member.

3. The means defined in claim 1 wherein said means limiting the radialprojection of said balls comprises a ring having apertures through whichsaid balls are adapted to project, the size of said apertures being lessthan the diameter of said balls, said ring being axially disposedbetween said members proximate the terminal portion of said groove, saidmembers axially positioning said ring with respect to said groove.

4. The means as defined in claim 1 and including a plurality of washersencompassing said fastening screws, said springs having one end bearingagainst said washers.

5. An arbor for retaining a workpiece having a multii stq s- 9a s r r smsr sins afirst and a second pair of axially positioned and relativelyseparable annular members respectively of a first diameter and a secondsmaller diameter, each of said pairs of annular members respectivelyhaving adjacent tapered wedging surfaces defining ball receivinggrooves; gripping balls in said grooves normally projecting radiallyfrom said grooves in response to the relative M axial approach of saidannular members of 5511 of said pairs of members;

means limiting the radial projection of said balls from their respectivegrooves;

first and second means respectively coupling said first pair and saidsecond pair of members;

means associated with each of said coupling means to bias theirassociated pair of annular members toward one another at predeterminedforces so as to normally radially project their associated balls fromsaid grooves;

means associated with each of said coupling means for selectivelycontrolling said predetermined forces;

means fixedly attaching a first annular member of said first pair ofmembers to a first annular member of said second pair of members suchthat said first annular members are movable as a unit; said firstannular members of each of said pairs of members having a hub portion onwhich the other, second annular members of each of said pair of membersis slidably mounted for movement toward and away from its associatedfirst annular member, said hub portion of said annular members of eachof said pairs being fixedly attached to one another, said second annularmembers of each of said pairs having bores and fastening screws slidablyextending therethrough and into a threaded engagement with bores in saidfirst annular members in each of said pairs and spring means carried insaid bores in said second annular members and engaging said fasteningscrews to bias said second annular members respectively toward saidfirst annular members.

1. A means for receiving and retaining a workpiece or the likecomprising: a pair of axially spaced and relatively movable membershaving adjacent tapered wedging surfaces defining a ball receivinggroove; gripping balls in said groove, said gripping balls normallyprojecting radially from said groove in response to the relative axialapproach of said members, said gripping balls being retracted into saidgrooves in response to the relative axial separation of said members;means limiting the radial projection of said balls from said groove whensaid members approach one another; means coupling said members to oneanother; said coupling means comprising a plurality of circumferentiallyspaced and longitudinally disposed bores in one of said members, aplurality of fastening screws extending through said bores andthreadedly engaging a plurality of axially aligned and circumferentiallyspaced threaded bores in the other of said members, a plurality ofsprings disposed in said first mentioned bores and wound around saidfastening screws, said springs engaging a portion of their associatedfastening screws and bores to bias said one member toward said othermember.
 2. The means defined in claim 1 wherein said other of saidmembers has a hub portion and said one member has a bore axial alignedwith and slidably engaging said hub portion such that said one member isaxially slidably movable on said hub portion to and away from said othermember.
 3. The means defined in claim 1 wherein said means limiting theradial projection of said balls comprises a ring having aperturesthrough which said balls are adapted to project, the size of saidapertures being less than the diameter of said balls, said ring beingaxially disposed between said members proximate the terminal portion ofsaid groove, said members axially positioning said ring with respect tosaid groove.
 4. The means as defined in claim 1 and including aplurality of washers encompassing said fastening screws, said springshaving one end bearing against said washers.
 5. An arbor for retaining aworkpiece having a multi-diameter cross section, said arbor comprising:a first and a second pair of axially positioned and relatively separableannular members respectively of a first diameter and a second smallerdiameter, each of said pairs of annular members respectively havingadjacent tapered wedging surfaces defining ball receiving grooves;gripping balls in said grooves normally projecting radially from saidgrooves in response to the relative axial approach of said annularmembers of each of said pairs of members; means limiting the radialprojection of said balls from their respective grooves; first and secondmeans respectively coupling said first pair and said second pair ofmembers; means associated with each of said coupling means to bias theirassociated pair of annular members toward one another at predeterminedforces so as to normally radially project their associated balls fromsaid grooves; means associated with each of said coupling means forselectively controlling said predetermined forces; means fixedlyattaching a first annular member of said first pair of members to afirst annular member of said second pair of members such that said firstannular members are movable as a unit; said first annular members ofeach of said pairs of members having a hub portion on which the other,second annular members Of each of said pair of members is slidablymounted for movement toward and away from its associated first annularmember, said hub portion of said annular members of each of said pairsbeing fixedly attached to one another, said second annular members ofeach of said pairs having bores and fastening screws slidably extendingtherethrough and into a threaded engagement with bores in said firstannular members in each of said pairs, and spring means carried in saidbores in said second annular members and engaging said fastening screwsto bias said second annular members respectively toward said firstannular members.